Topic: Gear Ratio/t-case opinions

[stan98tj]

a 2.72:1 ratio with the doubler part,

this is the part I'm not understanding. I see the atlas has two sticks, one for front axle and one for rear, correct? THese two sticks have a high and low range, correct? So if I am correct up until here, the high range would be 1:1, and the low range would be of your choosing, correct? But you mentioned it also has a 2.72:1, so how does that get engaged? Forgive me for all the questions, I'm just trying to fully grasp all the options available to me and am more than appreciative in the fact that I can talk to folks who actually run these systems...

[neale_rs]

this is the part I'm not understanding. I see the atlas has two sticks, one for front axle and one for rear, correct? THese two sticks have a high and low range, correct? So if I am correct up until here, the high range would be 1:1, and the low range would be of your choosing, correct? But you mentioned it also has a 2.72:1, so how does that get engaged? Forgive me for all the questions, I'm just trying to fully grasp all the options available to me and am more than appreciative in the fact that I can talk to folks who actually run these systems...

All correct. 
The 2.72 gets engaged with a third lever.  Some pics are on my build thread.

[sharpxmen]

with a twin stick t-case (forget about the doubler for now) you have a shifter for the front and one for the rear outputs (that go to the driveshaft yokes for each axle) - with these you can engage either front or rear, high or low independently for each axle, which means you can have rear hi (known with a regular 231 as 2wd or rear wheel drive hi), rear low (2wd still), front hi (front wheel drive) and front low. You would also have the ability to go 4wd hi and low just like with the 231. The doubler (crawl box) has it's own lever, what it does is to reduce the gear ratio between the trans and t-case, that means that when engaged would apply to whatever your t-case is set to (rwd hi/lo, fwd hi/lo or 4wd hi/lo), so if you have a t-case with a 4:1 ratio and a crawl box at 2.6:1 then when in 2wd hi with the dobler in low your combined ratio (doubler and crawl box) would be 2.6:1, if you engage low on the t-case you get to 10.4:1, you disengage the doubler you'll be at 4:1, then put the t-case back in hi and you're bact at 1:1.

there's some info and pics on the shifters i made (3 of them) in my Doubler (crawl box) build thread as well as when i did my NV3550+D300 install in the member's projects section (which had twin sticks at the time for front/rear independently).

[stan98tj]

You know, the more I read about it, the more the Atlas seems like a very viable option.
I just got off the phone with them and we talked a bit about their 4spd.
Here are some points:
Can still shift on the fly to 4hi
4 ratios are, 1:1, 2.72:1, 3.8:1, and 10.3:1
Will only shorten the length of the rear shaft by 2 inches, although I'll need a longer front shaft.
All in all, I get to keep my stock ratios and gain 2 low ratios.

Neale, I noticed the ratios you listed were a bit different (4.3:1 and 11.7:1???) if I remember. How did you get them to provide those gears?

[Jeffy]

You know, the more I read about it, the more the Atlas seems like a very viable option.
I just got off the phone with them and we talked a bit about their 4spd.
Here are some points:
Can still shift on the fly to 4hi
4 ratios are, 1:1, 2.72:1, 3.8:1, and 10.3:1
Will only shorten the length of the rear shaft by 2 inches, although I'll need a longer front shaft.
All in all, I get to keep my stock ratios and gain 2 low ratios.

Neale, I noticed the ratios you listed were a bit different (4.3:1 and 11.7:1???) if I remember. How did you get them to provide those gears?

You didn't talk to them about the different options available? http://www.advanceadapters.com/add_to_cart.php

[stan98tj]

:

You didn't talk to them about the different options available? http://www.advanceadapters.com/add_to_cart.php

Nothing is getting "added to cart" until this spring :)

[Jeffy]

:Nothing is getting "added to cart" until this spring :)

You can go to their site and configure the transfer case.  You will see there are many options that you probably haven't even considered...  http://www.advanceadapters.com/products/atlas4--atlas-4-speed-transfer-case/

[stan98tj]

You can go to their site and configure the transfer case.  You will see there are many options that you probably haven't even considered...  http://www.advanceadapters.com/products/atlas4--atlas-4-speed-transfer-case/

Very cool.
I can't remember, are you running an Atlas as well, Jeffy?
At any rate, I think this is probably what I'm going to get.

[Jeffy]

Very cool.
I can't remember, are you running an Atlas as well, Jeffy?
At any rate, I think this is probably what I'm going to get.

No, but I was very close to buying one.  Things changed and I went with a SYE instead to get the Jeep back up and running.  There's a wait for any of the Atlas's unless you find a shop who's got cases and gears in stock.

[stan98tj]

There's a wait for any of the Atlas's unless you find a shop who's got cases and gears in stock.

2 weeks or so according to the Advanced Adapter rep.

[neale_rs]

You know, the more I read about it, the more the Atlas seems like a very viable option.
I just got off the phone with them and we talked a bit about their 4spd.
Here are some points:
Can still shift on the fly to 4hi
4 ratios are, 1:1, 2.72:1, 3.8:1, and 10.3:1
Will only shorten the length of the rear shaft by 2 inches, although I'll need a longer front shaft.
All in all, I get to keep my stock ratios and gain 2 low ratios.

Neale, I noticed the ratios you listed were a bit different (4.3:1 and 11.7:1???) if I remember. How did you get them to provide those gears?

4.3 is better than 3.8 with the AX5.  Not sure what would be better with the auto.  It could be they have the 3.8 in stock and you might have to wait more for other ratios, they seem to push the 3.8.

[stan98tj]

:

4.3 is better than 3.8 with the AX5.  Not sure what would be better with the auto.  It could be they have the 3.8 in stock and you might have to wait more for other ratios, they seem to push the 3.8.

The torque converter multiPlies so I should be good with 3.8, right?

[neale_rs]

:The torque converter multiPlies so I should be good with 3.8, right?

3.8 with an automatic will be plenty low for the slowest, most technical crawling.  Going too low with an automatic leads to other issues like being unable to stop the Jeep with the brakes unless you put it in neutral.  Everything has a fix but one thing leads to another and more spending.

It's a great TC, no complaints.  It did have an o-ring leak but it was easy to fix and Advance Adapters sent me the o-rings free of charge.

[stan98tj]

3.8 with an automatic will be plenty low for the slowest, most technical crawling.  Going too low with an automatic leads to other issues like being unable to stop the Jeep with the brakes unless you put it in neutral.  Everything has a fix but one thing leads to another and more spending.

It's a great TC, no complaints.  It did have an o-ring leak but it was easy to fix and Advance Adapters sent me the o-rings free of charge.

Speaking of brakes, I'll have to upgrade for the 35s. Running disks all around, but def want to make sure I can stop.
Think I'll have an issue stopping in the lowest setting (10:1)?

[sharpxmen]

you don't need 10:1 unless you go with a manual, i would just get a 2 speed atlas if i were you, 4:1 would be plenty for anything with your transmission imo